Electronic devices widely use displays as output devices to present information in visual form. Examples of such electronic devices include televisions or computers. Typically, a video signal is either received by an electronic device or is generated within the device. In either case, an image is then displayed on the display. A number of displays are available, including Liquid Crystal Displays (LCDs), digital projectors, and the like.
Image quality often suffers due to various factors, including the limitations of high-resolution capture devices, transmission losses, and encoding/decoding losses. Thus, image enhancement techniques may be used to improve the quality of displayed visual images. One such image enhancement technique is brightness correction, which is applied statically after the user sets a gain level. However, as display dimensions and resolutions increase, static brightness correction is no longer adequate, because brightness can vary within a frame and among frames in video. Such variation stems from a number of factors, including limitations of high-resolution capture devices, transmission losses, encoding/decoding losses, and the like.
Recently, dynamic brightness correction has been introduced without noticeable success. Such solutions have been limited to dynamic brightness correction on the luminance component alone, which can lead to visible undesired effects, including faded colors and blurred edges. Problems seem to appear whenever dynamic brightness correction is applied to the luminance component of an image that has an object with mid-tone pixels on white background.